书面申诉 meaning in English

written appeal
written protest

If the other party fails to fulfill any provision of this agreement and fails to take remedial measures for the nonperformance in 30 days after receiving the written appeal notice which explains the relating circumstances , then the party may immediately terminated after sending the written notice
若对方未能履行本协议任何条款，且未能在收到说明有关情况的书面申诉通知三十（ 30 ）天内对此类违约行为采取补救措施，则可于(以)向对方发出书面通知后立即终止。